Optical fibers are used for a variety of applications including voice communication, data transmission and the like. With their ever increasing and varied use, it is apparent that efficient methods of splicing optical fibers are required. In order to efficiently couple the signals transmitted between respective optical fibers, the method of splicing the optical fibers must not significantly attenuate or alter the transmitted signals. Currently, there are two main methods for splicing optical fibers: fusion splicing and mechanical splicing. Mechanical splicing is a fiber optic mating system in which the ends of two optical fibers are brought into physical contact with each other and held in place by a mechanical force, such as a “cam” locking mechanism or a crimp. In other words, the optical fiber are aligned and butted together and then clamped in place to inhibit movement between the mechanical splice of the optical fibers.
Conventional mechanical splicing methods typically involve filling any gaps, hereinafter referred to as “core gaps”, between the fiber end faces with an index matching gel. The gel acts as a medium that transfers light between a field fiber and an optical fiber stub. Even though mechanical splices generally provide acceptable signal transmission characteristics, a mechanical splice can reflect a portion of the transmitted signal so as to produce a corresponding return loss. The reflectance is due, at least in part, to differences between the respective indices of refraction of the field fiber and the optical fiber stub. The index matching gel helps to reduce the differences in the indices of refraction between the fiber cores and the core gap.
To create a conventional mechanical splice, the ends of two fibers are typically cleaved and inserted into a mechanical splice assembly having precision fiber alignment features, such as machined or etched grooves running longitudinally through the assembly. The number of grooves and their respective dimensions are of a size to permit the fibers to rest within them. Typically, the fibers are cleaved using a mechanical cleaver that produces a substantially flat fiber end face either perpendicular or at a predetermined angle relative to the longitudinal axis of the fiber. Mechanical cleaves/cleavers may suffer from several disadvantages. First, they have an inherent glass defect zone that is a result of the mechanical blade striking the glass fiber. Second, they have sharp edges between the cleave face and the fiber outer diameter. This sharp edge can skive the groove components of the mechanical splice assembly. Third, they have substantially flat fiber end faces with cleave angles that can be non-perpendicular to the fiber outer diameter. This angle may increase the fiber core gap when the fibers are butted in the mechanical splice assembly, which increases attenuation. In addition to these disadvantages, mechanical cleavers require periodic cleaver blade replacement and are not automation friendly devices due to long-term instability.
In order to reduce back reflection, especially in high-power applications, the optical fibers may be mechanically cleaved at a predetermined angle. For instance, mechanical splice can have two mating fibers with respective end faces that are cleaved at an angle such as 8 degrees to eliminate back reflection at any index of refraction transition. Ideally, the two angles of the fibers in the mechanical splice (i.e., the end face angles on mating fibers) are matched or aligned to reduce core gap and thus optical signal loss of the mechanical splice. In practice it is difficult task to perform an angled cleave in a repeatable and reproducible fashion.
Thus there is a need for forming angled cleaves in optical fibers that overcome the disadvantages mentioned above for optical assemblies such as for mechanical splice connectors, especially mechanical splice connectors that carry high-power optical signals. The method should repeatable, reliable, and produce a fiber end face that is substantially free of defects. It would also be desirable to produce a shaped fiber end face that minimizes the core gap in applications in which it is mated to a field prepared fiber with a mechanical angled cleave. Preferably, the processing method is automation friendly, stable, and has no consumables that wear and affect performance of the angled cleave with use.